textproduct: Albany

WHAT HAS CHANGED

For today, will continue to mention the possibility of snow squalls with/ahead of a cold frontal passage. Then, snow transitions to lake effect snow that continues across far northern Herkimer and Hamilton Counties through Friday. With up to a foot of snow expected north of Rte 28, lake effect snow warnings have been issued this afternoon through Friday evening for northern Herkimer and Hamilton Counties.

Extreme cold moves in Friday afternoon and evening, and we have expanded the extreme cold watch to include southern Herkimer, eastern Rensselaer, and Berkshire Counties. Additional zones could be added over the next couple of forecast cycles as confidence continues to increase .

Finally, confidence continues in an impactful winter storm Sunday into Monday with widespread accumulating snow, heaviest south of I-90.

KEY MESSAGES

1) Scattered snow squalls could lead to briefly hazardous travel conditions today, with the highest chance from the Capital District north and west.

2) Heavy lake effect snow expected this afternoon through Friday evening across far northern Herkimer and Hamilton Counties.

3) High confidence for dangerous cold Friday night through Saturday resulting in an increased risk for hypothermia and frostbite.

4) Forecaster confidence has increased for a significant snow storm to bring moderate to major impacts to eastern NY and western New England Sunday through Monday with heavy snow amounts possible.

DISCUSSION

KEY MESSAGE 1: As of 2:30 AM EST...Current GOES 16 WV imagery shows broad upper troughing over the Great Lakes, with a negatively tilted shortwave currently near Lakes Erie and Ontario, with a closed upper level low (ULL) dropping south towards the western Great Lakes from Canada. At the surface, a 1003 mb low is situated near the Ontario/Quebec border, with its associated cold front back across the Great Lakes. With our area in the system's warm sector, there are still some scattered snow showers, with up to a few additional inches of accumulation possible north of I-90 through the morning hours.Highest snowfall amounts so far have been up to 4-5" across the foothills of the ADKs, so with a few additional inches of snow expected no changes were made to the existing advisory that will expire at 18z this afternoon. Temperatures are warmer than previous nights, with most areas in the 20s to low 30s.

As the sfc low tracks northeastwards today, its cold front will track from west to east across the region. With this cold front, scattered snow squalls will be possible, especially north and west of the Capital District where the best upper-level forcing and low-level lake enhanced moisture will be located. Steepening low-level lapse rates will lead to some low-level instability, which is helping drive the snow squall parameter >1 in numerical guidance. These squalls can be seen on radar across western NY at this time, and currently look more impressive than CAMs are showing. This initial line could track into western areas around or shortly after 12z this morning, but is expected to weaken as it does so. The better chance for squalls may be with the secondary cold front that comes through early this afternoon. Will continue to mention that the biggest threat is reduced visibility and roads quickly becoming snow covered. Despite air temps around or a couple degrees above freezing, flash freeze threat will likely be mitigated by below-freezing road temps from the recent very cold airmass.

KEY MESSAGE 2: Snow squalls come to an end behind the front this afternoon into early evening, at which point this will transition to a lake effect event. Behind the front, 850 mb temps drop to -15 to -18C over Lake Ontario, with inversion heights deepening to 700-750 mb. Low-level winds will be from the west, and will be fairly strong at 35-40 kt, which should allow the band to extend well inland into Herkimer and Hamilton Counties. Sustained westerly flow with little directional shear will keep the band positioned across northern Herkimer and Hamilton Counties, mainly north of Route 28, into Friday. Snowfall amounts under the band will likely reach 8-12", with locally higher amounts up to 15" possible in far northwestern Herkimer County near Stillwater Reservoir. Therefore, lake effect snow warnings were issued for these areas. Will also mention that the deep cold advection and a tightening pressure gradient will lead to breezy conditions region-wide behind the cold front this afternoon into tonight, and for areas in the lake effect band the combination of gusty winds and snow will lead to very difficult travel conditions.

KEY MESSAGE 3: Friday afternoon, an arctic cold front will track across the region as the ULL/TPV slides north of our region. This will cause the lake effect band to briefly shift south towards the western Mohawk Valley and northern Catskills, and it will eventually dissipate as winds veer to the NW behind the front. Some additional snow squalls can't be ruled out with this front on Friday, but moisture looks much more limited compared to Thursday, so confidence on whether or not any squalls will occur is still relatively low at this time.

This front will usher in the coldest airmass of the season so far, with 850 mb temps potentially reaching -30C across the ADKs. This will translate to low temperatures ranging from around 0 in the Mid Hudson Valley to around -20F in the ADKs Friday night. With a 1048 mb sfc high building over the northern Plains, the pressure gradient will once again strengthen across our region, leading to gusty winds that will make it feel even colder. Based on latest guidance and increasing winds from the NBM, we have expanded the extreme cold watch to include southern Herkimer County, the Rensselaer Plateau, and the Berkshires where apparent temps as low as -30F will be possible Friday night. For areas not in the watch, cold weather advisories will likely be needed as we get closer to this event and confidence on exact wind chills increases.

Saturday remains quite chilly with highs ranging from the negative single digits in the high terrain to single digits above zero for valley areas. Saturday night, there remains some uncertainty in just how cold we get. The sfc high will be moving overhead and winds diminishing, but high clouds will also be increasing ahead of the next storm system. Should clouds be slower to arrive/more breaks in the clouds, then lows could radiatively cool very quickly after sunset, while clouds arriving earlier would keep lows near or above the current forecast. Additional cold weather advisories may be needed for some areas Saturday night depending on how this scenario unfolds.

KEY MESSAGE 4: The ensembles and the medium range deterministic guidance continues to trend north/northwest with a primary and a secondary coastal low moving along the Mid Atlantic Coast late Sun/Sun night into Mon producing potentially a widespread moderate to heavy accumulating snowfall across eastern NY and western New England. Initially, arctic high pressure /~1040 hPa/ will be over NY and New England Saturday night into Sunday morning with a plethora of arctic air in place. Cold Weather headlines /Cold Weather Advisories and Extreme Cold Warnings/ will likely be needed Sat night/Sun morning for the County Warning Area. An inverted sfc trough associated with with low pressure over the Southeast/Lower MS River Valley will focus some snowfall over the region Sun morning into the afternoon. A secondary low forms near the VA/NC Coast late Sun pm/early Sun evening. The primary low weakens/decays over the Ohio Valley into western PA (associated with the inverted sfc trough), as the secondary coastal low takes control east of NJ and south of Long Island Sun night. The track continues to show less variability and more consensus on the majority of the guidance, as the coastal cyclone slows down Mon morning into the afternoon, which keeps the snow going over the vast majority of the forecast area. The moisture fetch from the Gulf and Atlantic is impressive, as QPF totals are approaching 1.0" over a large portion of the forecast area which with a high snow to liquid ratio may yield heavy/significant snow tallies. A 7th period Winter Storm Watch was discussed and it was decided with WPC and a majority of the collab offices (OKX/BOX/GYX/BTV) to wait another cycle.

The bottom line is that an extended period of moderate to heavy snowfall is supported by the NBM with 60-90% probabilities for snow Sun/Sun night into Mon. The latest 48-hr NBM guidance ending 7 pm Mon for >6" of snowfall indicates probabilities of 55-90% across the majority of the forecast with the highest probs from Albany south and east. 48-hr probabilities for >10" of snow for the same 48-hr period ending 7 pm or 00Z/Tue are 40-70%. Maybe have your yard sticks located and ready? The snowfall may potentially impact the Mon morning commute with the heavy snowfall. In the mid and upper level deformation zone to the departing storm system, additional snowfall could continue into Mon afternoon/Mon evening which would add onto the totals! The storm system is still 3-4 days out, but confidence has increased for moderate to major impacts for a moderate to heavy/significant snowfall. Snow to liquid ratios look to be above climatological values (12-20:1) with an arctic air mass in place, as high temps will be in the single digits to mid teens on Sun. Lows will be below zero over the southern Dacks and southern Greens Sun night and single digits over the majority of rest of the region. Highs on Mon only recover into the teens and lower 20s with some single digits over the mtns, as the snow tapers to flurries and snow showers by the Mon night time period. Below normal temps continue into the mid week.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Narrow broken lines of snow showers and squalls are currently moving across the region ahead of a cold front associated with a clipper system. Brief reductions to IFR are possible within these snow showers for KALB, KGFL and KPSF over the next hour or two. Visibility will be as low as 1SM and ceilings may lower to 2000-2500 ft.

Although southerly winds are currently about 5-10 kts ahead of the front, winds will become west to southwest at 10-15 kts within any snow squalls, as well as behind the passing front. Some gusts in the 20-30 kt range are possible within squalls and just behind the departing frontal boundary as well.

Behind the departing front, flying conditions should be VFR for the evening and into the overnight hours, with some lingering sct-bkn clouds around 4-5 kft. Gusty westerly winds will continue into the overnight, although they may briefly reduce towards daybreak Friday. However, winds will pick up within daytime mixing again on Friday, with some gusts again in the 20-25 kt range, especially for KALB and KPSF.

Flying conditions will generally be VFR on Friday. A passing snow shower can't be ruled out, but most of the lake effect activity will stay northwest of the region, with sct-bkn cigs around 4-5 kft through the entire day on Friday.

Outlook...

Friday Night: Low Operational Impact. Breezy. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: High Operational Impact. Definite SN. Sunday Night: High Operational Impact. Definite SN. Monday: High Operational Impact. Definite SN. Monday Night: Low Operational Impact. Slight Chance of SN. Tuesday: No Operational Impact. NO SIG WX.

CLIMATE

January 24

Record Cold High Temperatures:

Albany, NY: -1 degrees set in 1882 Glens Falls, NY: 0 degrees set in 1907 Poughkeepsie, NY: 8 degrees set in 1948

Record Cold Low Temperatures:

Albany, NY: -17 degrees set in 1948 Glens Falls, NY: -30 degrees set in 2011 Poughkeepsie, NY: -15 degrees set in 1961

ALY WATCHES/WARNINGS/ADVISORIES

CT...Winter Storm Watch from Sunday morning through Monday evening for CTZ001-013. NY...Winter Storm Watch from Sunday morning through Monday evening for NYZ032-033-038>043-047>054-058>061-063>066-082>084. Extreme Cold Watch from Friday evening through Saturday afternoon for NYZ032-033-038-042-054-082. Winter Weather Advisory until 1 PM EST this afternoon for NYZ032-033-082. Lake Effect Snow Warning until 7 PM EST Friday for NYZ032-033. MA...Winter Storm Watch from Sunday morning through Monday evening for MAZ001-025. Extreme Cold Watch from Friday evening through Saturday afternoon for MAZ001-025. VT...Winter Storm Watch from Sunday morning through Monday evening for VTZ013>015. Extreme Cold Watch from Friday evening through Saturday afternoon for VTZ013-014.